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UNITE STATES PATEN -OFF CE."

CARL RUMPFF, OF APRATH, NEAR ELBERFELD,'PRUSSIA, GERMANY.

MANUFACTURE-OF A NEWVCOLOR-PR'ODUCING ACID.IY

SPECIFICATION forming part of Letters Patent- No. 256,381, dated April11, 1882.

, Application filed April s, 1881. (Specimens) Patented in England March21,1881, in France March 31, 1881, in Belgium April f 15, 1881, and inGermany October 11, 1881.

To all whom it may-concern.-

Be itknown that I, CARL RUMPFF, residing at Aprath, near Elberfeld, inthe Kingdom of Prussia and Empire of Germany,- haveinvented a new anduseful Improvement in the Mannfacturc'of a new Color-Producing Acid,consisting essentially in the preparation and utilization of a newmonosulphonic acid of betanaphthol, of which the following is aspecification.

The action of the only monosulphonic acid of beta-naph'thol known up tothe present time upon the diazo compounds gives only very few colorreactions of technical value. I have succeeded, however, in preparing anew monosulphonic acid of beta-naphthol, and by means thereof inpreparing, partly by reaction upon the diazo compounds of the benzoleseries and naphthali'ne and partly by nitration, very val uable newcoloring-matters, the preparationwhereof is hereinafter described.

The nature and object of the present invention, therefore, is thepreparation and separation of the said new monosulphonic acid ofbeta-naphthol and of coloring-matters therefrom by nitration, or bycausing the same to react on diazo compounds, as hereinafter described.

Beta-nuphthol-mouosul phonic acid is formed (according-to Schaefer, Ann.Chem, 152, 296) by heating beta-naphthol on the water-bath with doubleits weight of commercial or English sulphuric acid till perfect solutionhas By means of the lead salt the acid is obtained in a pure state. If,however,

a the process of sulphonization is conducted in such a way that theduration of the reaction of the excess of sulphuric acid upon thenaphthol-monosulphonic acid already formed is as much as possibleshortened, and the attainment of too high a temperature is avoided, asecond isomeric naphthol-monosulphonic acid is formed besides thatdescribed by Scha'efer, which is very essentially difierent in all itsproperties from the abovementioned acid. It is especially in itsdifibrent behavior toward nitric acid that the new sul phonic acid isvery sharply distinguished from'the acid described which dye wool andsilklof a beautiful yellow;

Besides this, the difierence of the two isomeric monosulphonic acids isproved by the difi'erentsolubilitylof their respective neutralsodasaltsin spirits of wine of 90. The neutral soda salt of thebeta-monosulphonic acid described by Schaefer, G H ggjNm nearlyinsolublein boiling spirit of 90, while'the neutral soda salt of the newacid, on the contrary, dissolves therein with greatfaeility and settlesin beautiful and extremely hygroscopic crystals asthe alcohol cools. Thenew acid and its neutral soda salt may be separated from Schaefers acidand its neutral soda saltby this difference of solubility in alcohol.

In order to get a more copious yield of my new acid, (which I shalldesignate the alpha monosulphonic acid of beta-naphthol,) I pro-. ceedas follows: Onehundred kilograms of finelypowdered beta-naphthol freedfrom: moisture are mixed as quickly as possible with twohundredkilograms of commercial sulphuric acid, (66 The mixture heatsspontaneously with great rapidity; but care must be ture is only a fewdegrees higher, and it sulphuric acid is at the same time present inexcess,the new monosulphonic acid passes very quickly over into thecommon monosulphonic acid. The naphthol is very soon dissolved in thesulphuric acid. As soon as thispoint is reached (which generallyrequires no more time than ten to fifteen minutes, and which can be mosteasily recognized by the fact that when it is reached a sample of themelt saturated with ammonia gives a clear solution on the additionofdiazo-benzole) the meltis poured into cold water. It then contains amixture of two different su] phonic acids of beta-naphthol. The neutralsoda salts of the monosulphonic acids thus formed are prepared and driedin the usual manner. The crude mixture of these salts is treated withfrom three to four parts of boiling spirit of 90 and filtered hot. Thesoda salt of the nionosulphonic acid described by Schaefer remainsnearly perfectly undissolved. 'The salt of the new sulphonic acid,on thecontrary, passes into solution and crystallizes in finelarge crystals asthe solution grows cold, the mother-liquor being separated by amechanical method of separation. This spiritsoluble salt gives, incombination with the diazo compounds, coloring-matters fast against soapand light, the shades of which are on the whole yellower than those ofthe azo dye-stufl's prepared from the common beta-naphtholmonosnlphonicacid.

If I use for azotizing free amidoazo-benzole instead of itsmonosulphonic acid, I get a dyestufl' which possesses a somewhat moreyellowish, but withal extremely clear, shade. The homologues ofamidoazo-benzole and their lnonosulphonic acids give correspondinglybluer shades. Diazoazo-benzole and its homologues give with the newalpha-monosulphonie Stud.

Instead of the diazo compounds from benzole and its homologues,toluol-xylol, &c., the diazo compounds obtained from the other membersof the benzole series, which are not homologues in the ordinary sense ofthe term, may be employed-as, for instance, the diazo compoundsjorderivatives of ethyl-xylol, ethylbenzole, ethyl-methyl-Xylol, and othercompoundsofbenzole and its homologues with other alcoholic residues, asalso the diazo derivatives of the said bodies, which are substitutedwith the sulphonic group, all ot'which I comprehend in the generalexpression diazo compounds or derivatives of the bcnzole series, as wellas the diazoazo derivatives of the benzoles and naphthaline. Theseresults of the use of the new alpha-monosulphonic acid I do not hereclaim.

The alpha-monosulphonic acid of beta-naphthol (in contrast to themonosulphonic acid described by Schaefer) gives, when treated in aqueoussolution with nitric acid, nitro products the alkali salts of which arefine yellow dye-stuffs or coloring-matters easily soluble in water.

I am aware that beta-naphthol has been treated with sulphuric acid, bothcommercial and fuming, of various strengths, so as to form amonosulpho-acid of beta-naphthol but such attempts, owing to differencesof temperature exhibited and proportions of acid and naphthol, haveresulted in producing compounds possessing dili'erent chemicalconstitution or amounts of acid and base, and are of the nature ofmixtures of ditTerent sulphonic acids, and as yet no truemonosulpho-acid of betanaphthol has been so produced, while, on thecontrary, the compound formed according to the process herein describedresults solely in the production of a pure alpha-monosulphoacid ofbeta-naphthol.

Although I have described the making of various colors or dye-stuffs bythe use of the acid herein claimed, 1 do not here claim the process orthe separate coloring-matters, as

the same will constitute the subjects of other

